The ultimate aims of this research are to elucidate the mechanisms involved in maintenance of corneal hydration and transparency and to obtain information that may offer a basis for the control and treatment of corneal processes which produce blindness: 1. To continue the in vitro work to determine the basic mechanisms of ion transport in cornea and to determine the role of these mechanisms in the electrophysiology of fluid balance of the cornea. 2. To determine with the in vitro preparation the degree of electrical coupling between epithelial cells and eventually, if possible, between endothelial cells. 3. To perfect a perfusion technique on the intact globe which will enable us to determine the potential differences, electrical resistance, the corneal thickness and to visualize the epithelial and the endothelial cells and to measure the rate of movement of ions and water across these layers. These measurements will be made on a) the whole cornea, b) the cornea with the epithelium removed, and c) the cornea with the endothelium removed. 4. To explore the implications of what we consider a new concept for the control of corneal hydration. A brief account of this concept is given in the Preface.